The disclosure relates generally to resonant devices and, more particularly, to the start-up of resonant power converter circuits.
Resonant power converter circuits provide efficient power solutions for power supply design. A resonant power converter circuit is a type of power converter that provides direct current to direct current (DC-DC) conversion based on resonant current oscillation at a specific frequency. A switched resonant power converter contains one or more switching elements (e.g., one or more transistors) and reactive elements (e.g., capacitors and inductors) that, in connection with a periodic switching of the switching elements, generates a sinusoidal voltage or current. This voltage may then be rectified to produce a stable output voltage. Types of resonant power converters include a series resonant converter, a parallel resonant converter, and a series-parallel resonant converter.
A shortcoming of resonant converters is that, during start up, the converter may produce a high in-rush current and high voltage that may shorten the average life of the components that make up the converter and/or power supply in which the converter is implemented.
Accordingly, what is needed is a mechanism for effectively limiting high in-rush current and high voltage within a resonant converter during a power-up of the converter, without adding considerable power loss, solution size, cost and complexity.